Leadscrew

Abstract: Currently, the demand for high force density linear actuators is being met almost exclusively by employing a leadscrew and nut to transform rotary to linear motion. The paper describes an alternative technology, viz., a linear magnetic gear, which employs rare-earth magnets, and which simulation studies have shown to have a highly competitive force density.

Abstract: Drive means for a small, lightweight, easily operated syringe infusion pump. A syringe is secured in a holder and the syringe plunger is moved by a pusher block of the drive means. The pusher block is advanced to the syringe plunger by squeezing a finger tab. This simultaneously decouples the pusher block from the internal drive and opens the antisiphon catch to allow quick and easy set-up. The pusher block is moved by the engagement of a floating halfnut on a threaded leadscrew. A force is applied to the halfnut by the block substantially near the midpoint of the leadscrew thereby greatly reducing force mechanisms that attempt to separate the leadscrew and halfnut. A relatively light first biasing means is on the block for applying a relatively small force between the halfnut and the leadscrew.

Abstract: This disclosure relates to a landing gear system (10) that includes a landing gear strut (14) rotatable between stowed and deployed positions. An actuator (18) is connected to the landing gear strut, and includes main and emergency drives housed within a common body and operable independently from one another. A controller (32) in communication with the actuator (18) is configured to command the actuator between the stowed and deployed positions in response to an input. The controller (32) commands the main drive during a normal operating condition and commands the emergency drive in a failure condition of the main drive. The actuator (18) includes a body supporting emergency and main leadscrews arranged coaxially with one another. Main and emergency motors respectively are coupled to the main and emergency leadscrews. An output rod is supported by and extends from the body. The output rod is threadingly coupled to and is coaxial with the main leadscrew and configured to move axially in response to rotation of the main leadscrew. A brake selectively enables and disables the emergency drive.

Abstract: The invention features an apparatus for positioning a magnetic tape head transversely relative to a length of magnetic tape in a tape drive and includes a threaded leadscrew driven by a motor, a movable carriage for holding the tape head and having separated guide holes for receiving the threaded leadscrew and guiding the movable carriage axially along the leadscrew so that the resulting tape head motion is transverse to the direction of the tape. A leadscrew nut is connected to the movable carriage so that a threaded portion of the nut engages the leadscrew threads between the separated guide holes to propel the carriage axially along the leadscrew when the motor rotates the leadscrew. A spring is attached to the carriage and bears on the leadscrew nut so that the leadscrew nut threads are preloaded against the leadscrew threads. The guide holes include a pair of flattened surfaces forming a V-shaped groove parallel to the leadscrew and opposite the leadscrew nut so that the leadscrew nut bearing against the leadscrew preloads the leadscrew into the V-shaped groove of the guide holes.